AC Compressor screeching

[FriscoRat]

This is on my 2001 XLT w/4L SOHC.I changed the pulley and clutch hub w/new ones. Measured gap, it's OK. Pulley runs fine when engine running, but when AC is turned on and the hub engages, compressors seems to want to stop not spin, pulley stops, screeching begins and belts wants to melt. BY the way, the AC was cooling fine before all this began.

 

[8TZX]

The compressor itself may have locked up. Remove the belt and temporarily apply 12 volts to the clutch coil. Since you said the clutch appears to work, try and rotate the compressor manually. You should be able to rotate the compressor and feel some resistance. If you can't turn the compressor manually you will need to replace the compressor. I had the same problem on another vehicle. As soon as the clutch engaged, the belt would squeal, overheat and destroyed itself. The compressor had locked up. And like you, it worked perfectly until it didn't.

 

[FriscoRat]

The compressor itself may have locked up. Remove the belt and temporarily apply 12 volts to the clutch coil. Since you said the clutch appears to work, try and rotate the compressor manually. You should be able to rotate the compressor and feel some resistance. If you can't turn the compressor manually you will need to replace the compressor. I had the same problem on another vehicle. As soon as the clutch engaged, the belt would squeal, overheat and destroyed itself. The compressor had locked up. And like you, it worked perfectly until it didn't.

Thank you for the advice, I will do this tonight!

 

[FriscoRat]

The compressor itself may have locked up. Remove the belt and temporarily apply 12 volts to the clutch coil. Since you said the clutch appears to work, try and rotate the compressor manually. You should be able to rotate the compressor and feel some resistance. If you can't turn the compressor manually you will need to replace the compressor. I had the same problem on another vehicle. As soon as the clutch engaged, the belt would squeal, overheat and destroyed itself. The compressor had locked up. And like you, it worked perfectly until it didn't.

Update; ordered compressor and related components, guess I'll be busy on Memorial Day Weekend!